From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp6.wanadoo.fr (smtp6.wanadoo.fr [193.252.22.25]) by ozlabs.org (Postfix) with ESMTP id 6E6756822A for ; Thu, 1 Sep 2005 02:39:22 +1000 (EST) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf0601.wanadoo.fr (SMTP Server) with ESMTP id 75E001C00274 for ; Wed, 31 Aug 2005 18:39:15 +0200 (CEST) Received: from pegasos (AStrasbourg-251-1-27-135.w82-126.abo.wanadoo.fr [82.126.145.135]) by mwinf0601.wanadoo.fr (SMTP Server) with ESMTP id 53F301C0026B for ; Wed, 31 Aug 2005 18:39:15 +0200 (CEST) Date: Wed, 31 Aug 2005 18:33:13 +0200 To: "Mark A. Greer" Message-ID: <20050831163313.GA25391@localhost.localdomain> References: <20050830233205.GB24345@xyzzy.farnsworth.org> <20050831055934.871E41C00097@mwinf1107.wanadoo.fr> <20050831160417.GA3848@mag.az.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20050831160417.GA3848@mag.az.mvista.com> From: Sven Luther Cc: Nicolas DET , linuxppc-dev@ozlabs.org Subject: Re: Marvell MV6436xx ethernet driver patch List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Aug 31, 2005 at 09:04:17AM -0700, Mark A. Greer wrote: > On Wed, Aug 31, 2005 at 07:55:49AM +0100, Nicolas DET wrote: > > > This is a good idea. I suspect that most of the gain is from > > > turning off snooping and flushing/invalidating the cache explicitly. > > > Implementation-wise, I'd rather we not manipulate the MV643XX_ETH_BAR_? > > > registers directly in the driver. Today that is done in platform > > > setup code. This has promise but needs to be reworked. > > > > Yeah, the point was to have no snooping for this part of the chip. > > The descriptors in SRAM, and the data in DDR. This give a serious boost. > > > > I noticed MV643xx memory performances are really higher when turning > > off snoop (not only for ethernet). > > > > Well, I confess manipulating such thing here, is not totaly smart. > > However I don't really know where to put them. > > Maybe, somewhere in arch/ppc ? > > > > Because, at some pooint the driver will need to have this modified in order > > to reall work correctly. > > > > For example, if you use a module with that option (it will disable > > snooping) and then 'rmmod & modprobe' a new module without it will not work > > (no snooping as the new module expect!). > > > > Conclusion: yes, touching ETH_BAR isn't really well here, but where could > > we move it ? > > The enet->mem BARs are configured in > arch/ppc/syslib/mv64xc60.c:mv64360_config_io2mem_windows(). Which is not used in the pegasos code path, as we are chrp though. Friendly, Sven Luther